1. Field of the Invention
This invention relates to a magnification change-over device adapted for a camera having a photo-taking lens and a viewfinder arranged independently of each other.
2. Description of the Related Art
Cameras of the kind having the magnification thereof variable by means of a zoom lens or the like have been known.
The cameras of this kind include a type called a single-lens reflex camera which is arranged to form a viewfinder optical system by using the optical path of a photo-taking optical system. In the case of the single-lens reflex camera, the magnification of the viewfinder automatically changes when that of the photo-taking lens is changed. Whereas, in the case of a camera of another type having the viewfinder optical system arranged completely independent of the photo-taking optical system, the magnification of the viewfinder cannot be changed by merely changing that of the photo-taking lens. In the event of the camera of this type, therefore, the camera must be provided with some interlock device for causing the magnification of the viewfinder to change according to a change in the magnification of the photo-taking lens.
However, in accordance with the arrangement of the conventional interlock device which is provided for the above-stated purpose, the magnification of the photo-taking lens comes to change every time the magnification of the viewfinder is changed during the process of composing a picture. Therefore, in case that a photographing operation is stopped halfway in the process of selecting a picture composition, the camera must be brought back to a stowed state by shifting the photo-taking lens to its initial position. This is a troublesome operation. In addition to this, in case where the photo-taking lens is arranged to have its magnification shifted by means of a motor, the loss of energy for the operation has presented another problem.